Avalanche protection system

ABSTRACT

Apparatus is described for arresting or at least retarding an avalanche. In the described embodiment the apparatus comprises a plurality of elongate substantially cylindrical bodies ( 1 ) which are positioned on a mountainside in a likely avalanche path, for deployment into an avalanche. Each body is provided with a multiplicity of bristles ( 10 ) for engaging with one or more of the other cylindrical bodies ( 1 ) with which it may come into contact when the bodies are deployed. The bristles may be provided with locking mechanisms such as hook and loop mechanisms ( 14,16 ) for locking one cylindrical body to another when the bristles ( 10 ) of each come into contact. Each body may further be provided with anchor cables ( 26 ) to brake and arrest the body when deployed into an avalanche. The apparatus includes one or more stands ( 2 ) for deploying the cylindrical bodies into an avalanche. In use the stand(s) are fixed to the mountainside in strategic positions in the predicted avalanche path.

RELATED APPLICATIONS

This application claims priority to PCT Application No.PCT/GB2004/005143, dated Dec. 3, 2004, the content of which isincorporated herein by reference. That application claims priority to UKApplication No. 0327965.0 filed Dec. 3, 2003.

FIELD OF THE INVENTION

The invention relates to an avalanche protection system in particular,though not exclusively, for deployment near ski resorts or residentialareas where an avalanche can occur.

BACKGROUND OF THE INVENTION

It is well known that almost two hundred people a year are killed byavalanches around the world. As skiing and other winter sports arebecoming more popular this number will unfortunately increase. Skiresorts and residential areas normally have no warning of an impendingavalanche. This is a particular problem at night time when most peopleresident in the areas are sleeping.

SUMMARY OF THE INVENTION

An object of the present invention is to provide front line protectionto the residents of a winter sports resort or a town where avalanchescan occur. Another object of the invention is to provide a device whichwill arrest or at least retard the flow of ice and snow in an avalanchein order to save life and property.

According to a first aspect of the invention there is provided avalancheimpeding apparatus comprising a plurality of elongate bodies anddeployment means for deploying said bodies into an avalanche, each bodybeing provided with engaging means for engaging with at least one othersaid body with which it may come into contact when the bodies aredeployed.

Preferably the elongate bodies are each substantially cylindrical.Preferably, the engagement means comprises a multiplicity of bristlesextending outwardly from a central tubular portion of each body.Preferably, the bristles are mounted in a spaced apart relationshipalong substantially the whole length and circumference of the centraltubular portion.

The engagement means may further include automatic locking means forlocking automatically each body to any other said body with which itcomes in to contact. The locking means may, for example, comprise atleast one hook and loop locking mechanism provided on at least some ofthe bristles. Preferably, each bristle is provided with a plurality ofhooks, and a series of loops configured for engaging with the hooks onother ones of said bristles. The hooks may be arranged in a spaced apartrelationship in lines extending generally parallel to the axis of thebristle with each hook preferably extending generally perpendicularly tothe axis of the bristle.

Preferably at least one of the elongate bodies further comprises atleast one anchor cable attached at one end to the elongate body andsecured, in use, to the ground by fixing means at or near the other endof said cable. Conveniently if more than one anchor cable is used, thecables are attached to the elongate body in a spaced apart relationshipalong the length of the elongate body.

Preferably the at least one of the elongate bodies further comprises aplurality of anchor cables, each attached at one end to said elongatebody, said anchor cables being interconnected by at least one bracingelement and, in use, being secured to the ground by fixing means at ornear the other end of the cable.

Most preferably a plurality of bracing elements are used andinterconnect the anchor cables to form a lattice or net like structure,of cables and bracing elements, when the cables are deployed on a slope.Desirably the bracing elements may interconnect the anchor cables atmore or less regular intervals along the length of the cables.

When being deployed ready for use each anchor cable is laid out alongthe ground, at a time when snow is generally absent, in a directiongenerally away from the elongate body, generally downhill on a slopewhere an avalanche may be expected. If a plurality of anchor cables isemployed, the cables are laid out in a spaced apart relationship runninggenerally downhill. Where bracing elements are used the lattice or netlike structure is laid out on the hillside, downhill of the location ofthe elongate body. The bracing elements may be cables, rods or bars forexample.

In use, the anchor cables are secured to the ground by fixing means atone or more attachment points near the end of the cables distant fromthe elongate bodies. The attachment points may be on the anchor cables,the bracing elements or at the connections between cables and bracingelements. When an avalanche occurs the anchor cables act to brake andarrest the elongate bodies as described hereafter.

The deployment means may comprise at least one stand for holding one ormore of said bodies prior to deployment. The stand is preferablyconfigured to be mounted on a mountainside. Preferably, the stand isformed and arranged to hold several of said bodies. The bodies arepreferably held generally horizontally and one above another, betweentwo generally vertical end supports of the stand. This has the advantagethat each body is deployed from a different height, into the avalanche.The stand may be formed and arranged so that the bodies simply rest onthe stand with any attached anchor cables laid out generally downhillfrom the stand, but are free to move out of the stand under the force ofan avalanche hitting the stand. Desirably at least one of the elongatebodies held in a stand has a said at least one anchor cable attached.Preferably all the elongate bodies have a plurality of anchor cablesattached. Most preferably all of the elongate bodies have attached aplurality of anchor cables, interconnected with bracing elements,forming a lattice structure of cables and bracing elements.

Alternatively the deployment means may conveniently further include atleast one sensor for sensing an avalanche and activation means incommunication with the sensor(s) and configured to deploy said elongatebodies upon receiving a signal from the sensor(s) that an avalanche hasbeen detected. The activation means may be designed to deploy the bodiesby forcing them out of the stand into the path of the avalanche or,alternatively, may be designed to simply release the bodies (for exampleby releasing a retaining means which may be holding the bodies in thestand) so that they are free to move whereby they will be pulled out ofthe stand by the force of the avalanche when the avalanche hits thestand. The sensors may be motion and/or acoustic sensors, or any othertype of sensor capable of detecting an avalanche approaching the stand.

In practice, the deployment means preferably comprises several standseach preferably holding several of said bodies, the various stands beingplaced strategically at different positions on a mountainside where anavalanche is likely to take place. The anchor cables or lattice ofbraced anchor cables from each elongate body (where fitted) are laid outin a spaced apart relationship downhill from each stand and fixed to theground by appropriate fixing means at their attachment points.

The invention then works in the following manner. When an approachingavalanche is detected by the deployment sensors in the uppermoststand(s)the elongate bodies on those stands are released into theavalanche. Alternatively where sensors are not used the elongate bodiesare dislodged from the stands by the force of the avalanche. As theavalanche tumbles down the mountainside the energy from the avalanchecauses the bodies to lock together as they touch one another (by meansof the bristles and hook and loop mechanisms on the bristles) so thatthey become one or more larger units. This absorbs the energy of theavalanche and reduces the airflow in the avalanche. At the same time asthe elongate bodies descend the mountainside with the avalanche theirattached anchor cables are pulled out from under the original snow coveron the ground causing a braking action. The elongate bodies are broughtto stop, or at least slowed substantially, by virtue of the fixing meansholding the anchor cables to the ground at their attachment points.

Where a plurality of anchor cables are used on a given elongate bodythis braking action can be further enhanced by the provision of panelsconstructed of, for example cloth or sheet metal, attached betweencables or between cables and bracing elements. As the elongate bodiestravel downhill during an avalanche the panels provide enhanced brakingaction by virtue of the energy they expend in lifting the original snowcover from the slope, or by their interaction with the snow and air massof the avalanche.

By arranging several sets of cylinders at different intervals down theavalanche slope this will ensure that if the avalanche snow and icetakes a path past or over the first set of cylinders then the next setof cylinders positioned further down the slope will be deployed tofurther retard the avalanche.

The bodies may be made from carbon fibre and/or plastics material.Preferably the central tubular portion of each body is made of stainlesssteel or carbon fibre. The bristles are preferably made from glass fibreor a plastics material. The length of each body may be in the range often to fifteen metres, the diameter of the central tubular portion maybe approximately one metre and the length of the bristles may be betweenone and two metres. The cables may be made from steel and are preferablyabout 50 metres in length. Longer or shorter cables may be employeddepending on the requirements of the location in which the avalancheprotection system is being deployed. The bracing elements are alsopreferably made of steel or steel cable. The fixing means, used toattach the cables to the ground at their attachment points may compriseany suitably strong means, for example bolts screwed directly into theground or into a concrete structure such as a block buried in theground.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described by way ofexample only and with reference to the accompanying drawings in which:

FIG. 1 is a front view of an avalanche impeding apparatus according toone embodiment of the invention;

FIG. 2 is a detailed view of a portion of the apparatus of FIG. 1;

FIG. 3 is an end view of a cylinder provided with bristles;

FIG. 4 is a detailed side view of a bristle provided with a hook andloop locking mechanism;

FIG. 5 is a schematic view of an elongate body (cylinder) with a latticeof anchor cables and bracing elements attached according to oneembodiment of the invention;

FIG. 6 is a schematic side view of a mountainside showing avalancheprotection apparatus deployed thereon;

FIG. 7 is a perspective view of four substantially cylindrical bodies ofan avalanche impeding apparatus according to another embodiment of theinvention;

FIGS. 8(a) and (b) illustrate schematically a portion of a mountainsideprovided with avalanche impeding apparatus according to the invention,FIG. 8(a) showing the mountainside before the avalanche and FIG. 8(b)illustrating the mountainside after an avalanche has fallen; and

FIG. 9 is a detailed end view of a stand forming part of the apparatusof FIG. 1.

For clarity the anchor cable or cables that may be attached to theelongate bodies (cylinders) are omitted from FIGS. 1-3 and 6-8.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT

FIG. 1 shows avalanche impeding apparatus for arresting or at leastretarding an avalanche. The apparatus comprises a number of cylinders 1(five shown) mounted on a stand 2 in which the cylinders are arranged inparallel one above the other. In use of the apparatus, the stand 2 ispositioned on a mountainside in a likely avalanche path. The stand isfixed to the ground such that the cylinders 1 are held horizontallyrelative to two generally vertically extending end supports 4, 6 of thestand 2. The stand may be fixed to the ground by means of bolts or pilesscrewed through a base plate 8 (shown in FIG. 9) of the stand, or by anyother suitable means. Attached to each cylinder 1 are long bristles 10which are arranged in spaced apart relationship along the full length ofthe cylinders 1 and around the full circumference of each cylinder 1.The bristles 10 extend outwardly from an outer cylindrical surface 12 ofthe cylinders 1, in the preferred embodiment extending perpendicularlyto this cylindrical surface, as shown in FIG. 3. In this embodiment thecylinders 1 are made from stainless steel or a carbon fibre material andthe bristles are made from glass fibre or a plastics material, thebristles being permanently attached to the cylinders 1 by means ofadhesive and/or mechanical mounting means e.g. screws. In thisembodiment the length of each cylinder is 10 metres and the diameter ofthe cylinder (not including the bristles) is 1 metre and the length ofeach bristle is 1.5 metres. However, other dimensions are also possible.

Half way along the length of each bristle 10, from the mid-point to thefree end of the bristle 10, locking mechanisms are provided in the formof hooks 14 and loops 16. The hooks are mounted in lines extendingparallel to the axis of the bristle and the loops are provided in theform of a mesh 17 also extending in a direction generally parallel tothe axis on the bristle, as shown in FIG. 4. In this embodiment thereare two lines of hooks 14 provided on each bristle, and two lines ofloops 16 arranged between the lines of hooks. The hook and loopmechanisms lock one cylinder 1 to another when the bristles of any twocylinders engage after the cylinders have been deployed into anavalanche.

The cylinders 1 are held in place in the stand 2 by means of a centralshaft 18 provided in each cylinder 1 which shaft protrudes from the endsurfaces 20, 22 of each cylinder 1 and which slides into and rests in acomplimentary recess 24 (see FIG. 9) provided therefor in the endsupports 4,6 of the stand 2. In this embodiment the shafts 18 are simplysitting in the recesses provided therefore on the stand 2 (see FIG. 9),these recesses 24 being configured as slots angled such that when anavalanche hits the stand 2 the cylinders are simply pulled out of thestand by the force of the snow and ice in the avalanche. However, in analternative embodiment the stand may be provided with sensors fordetecting the approach of an avalanche and activating an actuation meanswhich deploys the cylinders into the avalanche. In this case, forexample, the cylinder shafts 18 may be held in the stand by a lockingmeans (not shown) which is actuated by the sensor to release thecylinders upon detection of an approaching avalanche. Alternatively, theactuation means may be configured to physically eject the cylinders fromthe stand upon detection of an approaching avalanche by the sensors. Inany of these embodiments once the cylinders 1 have been deployed thecylinders will lock together as the avalanche tumbles down themountainside and this will arrest the snow and ice and reduce theairflow and energy of the avalanche. This has the effect of reducingfriction between the falling snow and ice. It is this friction in thesnow and ice which causes it to melt, initiating and/or continuing theavalanche. When the friction is stopped or reduced the snow and icetends to freeze up again thereby stopping or reducing the avalanche.

The cylinders lock together by means of the hook and loop mechanismsprovided on the bristles 10. It will be appreciated that the cylindersare moved down the avalanche path by the energy of the avalanche andalso partly by gravity. The extent to which the cylinders proceed downthe slope is limited by the braking and anchoring effect of attachedanchor cables where fitted, (not shown but see FIG. 5) together with theeffect of their locking together.

In practice, several stands 2 each containing several of the cylinders 1will be positioned on an avalanche slope at different intervals down theslope, such that if avalanche snow and ice takes a path past or over afirst set of cylinders arranged in one or more stands positioneduppermost on the hillside, then one or more further sets of cylinderspositioned further down the slope will be released. If there are noavalanche sensors provided, and the cylinders therefore simply rest inrecesses provided in their respective stands, the lower cylinders willsimply be pulled out of the lower stands when snow or ice, or a higherand earlier released cylinder, hits the lower cylinder(s).Alternatively, if a sensor system is provided, it may for example beconfigured to release the lower cylinders at predetermined sequentialtime intervals after release of the first released cylinders, or upondetection of the impact of another cylinder. The stands should bearranged so that all the cylinders are substantially parallel to oneanother (this tends to encourage the cylinders to lock together whenthey are deployed into the avalanche). This is illustrated schematicallyin FIGS. 8(a) and (b) in which each horizontal straight line representsone cylinder 1.

FIG. 5 shows schematically a typical arrangement for the attachment ofanchor cables and bracing elements to an elongate element of theinvention. The cylinder 1 (elongate element) has attached at intervalsalong its length a number of anchor cables 26, typically made of steel.Bracing elements 28 and 30 connect the anchor cables 26 to form alattice structure. In this example the bracing element 28 is a steel barwhich assists in keeping cables 26 spaced apart near their attachmentpoints to the cylinder, helping to prevent snagging of the cables withthe cylinder and aiding the evenly spaced deployment of the cablesdownhill of the cylinder. Additional cables 32 have been provided inthis example at each extremity of the bracing element (bar) 28. Theother bracing elements 30 are steel cables. The spaces 34 between thecables and the bracing elements can be fitted with panels of cloth orsheet metal to provide additional braking in use if needed. In use, thecable and bracing element lattice is deployed generally downhill fromthe stand in which the cylinder 1 is located. It is attached to theground by fixing means at attachment points 36, distant from thecylinder 1. When a cylinder 1 is deployed into an avalanche thisarrangement allows maximum opportunity for interaction between theavalanche and the cylinder and with other deployed cylinders before thecylinder 1 is stopped by the anchor cables 26 at the limit of possibledownhill travel.

FIG. 6 shows schematically a multiplicity of deployed cylinders 1tumbling down a mountainside 38 in an avalanche 40. FIG. 7 shows fourslightly modified versions of the cylinders 1 of FIG. 3, showing how thebodies engage via the bristles 10. In the FIG. 7 embodiment each body isin the form of a substantially cylindrical central portion havingrounded ends 40, rather than flat ends as in the embodiment of FIGS. 1to 3.

The cylinders are placed onto the stand at heights which should avoidthe apparatus simply being buried by snow. For example, the lowermostcylinder may be placed at a height of about 6 to 8 metres above thesurface of the hillside. If desired each cylinder may be wrapped in athin bag, for example a thin PVC bag, to prevent snow or ice build up onthe cylinders. However if there is a heavy fall of new snow it may benecessary to place an additional cylinder in each stand, on top of theexisting cylinders.

It will be appreciated that as the cylinders 1 lock together afterdeployment they form one or more larger units which in turn may locktogether to form a single body which comes to rest on the hillside. Thismay also have the advantage of forming a wall to any snow and icecontinuing to fall down the hillside on to them. The resulting effect isthat the avalanche is significantly retarded and/or prevented fromprogressing any further down the hillside and therefore people andproperties located further down the slope are safe.

It will be appreciated that various modifications to the above describedembodiments are possible without departing from the scope of theinvention as claimed.

1. Avalanche impeding apparatus comprising a plurality of elongatebodies (1) and deployment means (2) for deploying said bodies into anavalanche, each body being provided with engaging means (10) forengaging with at least one other said body with which it may come intocontact when the bodies are deployed.
 2. Avalanche impeding apparatusaccording to claim 1, wherein each said elongate body (1) issubstantially cylindrical.
 3. Avalanche impeding apparatus according toclaim 1, wherein each said elongate body (1) comprises a central tubularportion and a multiplicity of bristles (10) extending outwardly from thecentral tubular portion.
 4. Avalanche impeding apparatus according toclaim 1, wherein the bristles (10) are mounted in spaced apartrelationship along substantially the whole length and circumference ofthe central tubular portion.
 5. Avalanche impeding apparatus accordingto claim 1, wherein the engagement means further includes automaticlocking means for locking automatically each body to any other said bodywith which it comes into contact.
 6. Avalanche impeding apparatusaccording to claim 1, wherein the locking means comprises at least onehook and loop mechanism (14,16) provided on at least some of thebristles (10).
 7. Avalanche impeding apparatus according to claim 1,wherein each bristle (10) is provided with a plurality of hooks (14) anda series of loops (16) configured for engaging with the hooks on otherones of said bristles.
 8. Avalanche impeding apparatus according toclaim 1, wherein the hooks (14) are arranged in spaced apartrelationship in lines extending generally parallel to the axis of thebristle (10) with each hook extending substantially perpendicularly tothe axis of the bristle.
 9. Avalanche impeding apparatus according toclaim 1, wherein at least one of said elongate bodies (1) furthercomprises at least one anchor cable (26) attached at one end to the saidelongate body, said anchor cable, in use, being secured to the ground byfixing means at or near the other end of said anchor cable. 10.Avalanche impeding apparatus according to claim 1, when more than oneanchor cable (26) is used, wherein the said anchor cables are attachedto said elongate body (1) in a spaced apart relationship along thelength of said body.
 11. Avalanche impeding apparatus according to claim1, wherein at least one of said elongate bodies (1) further comprises aplurality of anchor cables (26) each attached at one end to saidelongate body, said anchor cables being interconnected by at least onebracing element (28,30) and said anchor cables, in use, being secured tothe ground by fixing means at or near the other end of said anchorcable.
 12. Avalanche impeding apparatus according to claim 1, whereinsaid plurality of anchor cables (26) are interconnected by a pluralityof bracing elements (28,30) formed and arranged, in use, to form alattice structure of said anchor cables and bracing elements. 13.Avalanche impeding apparatus according to claim 1 wherein at least onepanel of cloth or sheet metal is fitted between anchor cables (26) orbetween anchor cables and bracing elements (28,30) to act as a brakingdevice in use of the apparatus.
 14. Avalanche impeding apparatusaccording to claim 1, wherein the deployment means comprises at leastone stand (2) for holding one or more of said elongate bodies (1) priorto deployment.
 15. Avalanche impeding apparatus according to claim 1,wherein the stand (2) is formed and arranged to hold several of saidelongate bodies (1).
 16. Avalanche impeding apparatus according to claim1, wherein all of the elongate bodies held in a stand have a pluralityof anchor cables (26) attached.
 17. Avalanche impeding apparatusaccording to claim 1, wherein each elongate body (1) held in a stand (2)has a plurality of anchor cables (26) attached which are interconnectedwith bracing elements (28,30) formed and arranged to form a latticestructure of said anchor cables and bracing elements.
 18. Avalancheimpeding apparatus according to claim 1, wherein the bodies (1) are heldgenerally horizontally and one above another between two generallyvertical end supports (4,6) of the stand.
 19. Avalanche impedingapparatus according to claim 1, wherein the end supports (4,6) areformed and arranged so that the bodies (1) rest on the stand but arefree to move out of the stand under the force of an avalanche hittingthe stand.
 20. Avalanche impeding apparatus according to claim 1,wherein the deployment means further includes at least one sensor forsensing an avalanche, and activation means in communication with thesensor and configured to deploy said elongate bodies upon receiving asignal from the sensor that an avalanche has been detected. 21.Avalanche impeding apparatus according to claim 1, wherein the sensor isa motion and/or acoustic sensor capable of detecting an avalancheapproaching the stand.
 22. Avalanche impeding apparatus according toclaim 1, wherein the deployment means comprises several stands (2)holding said elongate bodies (1).
 23. Avalanche impeding apparatusaccording to claim 1, wherein the length of each elongate body (1) is inthe range of ten to fifteen metres.
 24. Avalanche impeding apparatusaccording to claim 1, wherein the length of the bristles (10) is betweenone and two metres.
 25. A method of impeding an avalanche, comprisingplacing the avalanche impeding apparatus of claim 1 on a mountainside inthe predicted path of an avalanche and fixing the stand (2) of saidapparatus to the mountainside in said predicted path.
 26. A method ofimpeding an avalanche, comprising positioning the avalanche impedingapparatus of claim 1 on a mountainside in the predicted path ofavalanche and so that the plurality of stands (2) are strategicallypositioned at different positions on the mountainside.
 27. The methodaccording to claim 26, wherein the stands (2) are positioned and fixedto the mountainside such that the cylinders (1) in all the stands aresubstantially parallel.